[PtJudeRI]

Installed the tuna and shark magnets in my engine room, using the fluid chamber to transmit through the hull. I have the toggle switches mounted up in the FB. I thought it came out pretty well. The group buy seems to be going well guys, a good product, I'm happy so far!

Ryan

 

[MakoMatt]

Ryan, thanks, looks like you did a pro job. Hang mine over the side in a Killey cart to protect it.

Question, can you see, hear, or notice any differences between the Mako & Tuna Magnets??

MakoMatt

 

[JMetaxas]

Ryan: Are you confident these are strong enough to transmit through the hull? I just wonder how much is lost in the fiberglass.


John

 

[PtJudeRI]

Matt,

The only thing that I noticed is that there is a difference in the pitch of the "hum" that the two make. Its slight, and I had to listen at the dock with nothing running, but I heard something... Not really sure about what is lost in the fiberglass, but I know that they recommend installing it with a fluid chamber between the magnet and the hull to improve the resonance.

 

[carlynewlondon]

What did you use for a fluid chamber.

 

[PtJudeRI]

Chamber

I dont have anything drawn out, but here was the process...
The lower ring is solid, with one side access hole to attach a spigot to fill the dead space with oil ( you can fill it with anything you like, so long as its liquid). This is affixed to the hull with 5200. The mako/tuna magnet then rests on top of that ring, with a bead of silicone in between that and the lower ring, to create a sealed chamber for oil to sit in. Then, the upper ring was slid over the assembly and screwed down to the lower ring, wedging the magnet in place further. The lower ring is 3/4 inch smaller than the diameter of the magnet, and is 2.75 inches in diameter, the upper holding ring is 2" in diameter, and slightly wider than the diameter of the magnet. I have the fill caps in there in case I ever get a leak, i can just refill in a pinch before I have to reseal it, but this hasn't happened yet, and they have been in for two years now.

 

[carlynewlondon]

Did you have the rings custom machined or did you find something off the shelf?

 

[PtJudeRI]

The Rings were custom machined in New Bedford, the guy who did it is very knowledgeable in marine fabrication and does an excellent job. Brodeur Machine is the name of the co, I think.

Ryan

 

[MakoMatt]

bump for seaja3

MakoMatt

 

[asiegel]

I had not looked at this before, but it looks very good. My question is, has anyone gone in the water to listen whether the sound actually comes through the hull?

 

[lowlands]

Transducers are frequently mounted to shoot through a hull. Granted, it's a much higher frequency signal, but as long as the hull isn't cored or steel it works fine.

Airmar has said that fiberglass has almost the same density as water, and is relatively invisible to sound waves as long as they don't have to pass through air before getting there.

What you want to make sure of is that there are no air voids or crazing in the glass.

Some people say you lose a 1/3 of the signal though. I don't know if that's true, but for one of these noisemakers it shouldn't matter.

 

[654455]

Thanks for the bump Matt

 

[leakyrivot]

I've got a hollow aluminum engine bracket (twin outboards)..

With mine I just put 5200 around the aluminum rim and stuck it down just enough so that both surfaces touched the sealant. I left a little space on the uphill side so it could fill with water.

Granted I've got one ring from an old mako magnet still left there which I can't remove, it works great, and there's pleanty of space left for replacing them during the lifetime of the bracket.

Jon